The all-in-one (AIO) printer is a multi-function device that typically includes at least a printer and a document scanner in a single, compact package. Its reduced footprint, lower cost, and versatility make the AIO printer a desirable architecture for desktop print and document handling applications.
Many multi-function printers use a carriage-based printer, such as an inkjet carriage printer, which has advantages in size, performance, and cost. In the inkjet carriage printer, a printhead is mounted in a carriage that is moved back and forth across the region of printing. To print an image on a sheet of paper or other recording medium (sometimes generically referred to as paper herein), the recording medium is advanced a given distance along a recording medium advance direction and then momentarily stopped. While the recording medium is stopped and supported on a platen, the printhead carriage is moved along a carriage scan direction. The carriage scan direction extends substantially perpendicular to the recording medium advance direction. In the course of printhead travel along the carriage scan direction, controllable marking elements in the printhead record marks on the recording medium—for example by ejecting drops from an inkjet printhead. After the carriage has printed a swath of the image while traversing the recording medium, the recording medium is advanced incrementally, the carriage direction of motion is reversed, and marking is repeated with printhead movement in the reverse direction. By repeating this process a number of times, the printer forms the image onto the recording medium, swath by swath.
Internal printer components provide controlled movement of the recording medium in one direction, coordinated and synchronized with controlled movement of the printhead along the carriage scan direction. Providing this type of controlled movement requires a stable support structure for the various moving components and media.
By way of example, FIG. 1 shows a portion of a prior art carriage printer. 300, with some parts hidden so that other parts can be more clearly seen. Printer 300 has a printing region 303 across which a carriage 200 is moved back and forth along a carriage scan direction 305 that extends along the X axis between the right side 306 and the left side 307 of printer 300 while printing on recording medium that is supported by the platen that provides printing region 303. Carriage motor 380 moves a belt 384 to move carriage 200 back and forth along carriage guide rail 382. In this way, carriage 200 is actuable to move along a carriage scan direction 305. Printhead 250 is mounted in carriage 200, and ink supplies 262 and 264 are mounted in the printhead 250. In this orientation of printhead 250, the droplets of ink are ejected downward onto the recording media in printing region 303 in the view of FIG. 1. Ink supply 262, in this example, contains five ink sources cyan, magenta, yellow, photo black, and colorless protective fluid, while ink supply 264 contains the ink source for text black.
Paper, or other recording medium is loaded along paper load entry direction 302 toward the front 308 of printer 300. Printed paper traveling from the rear 309 exits along direction 304. A feed roller 312 includes a feed roller shaft along its axis, and a feed roller gear 311 is mounted on the freed roller shaft. The motor that powers the paper advance rollers is not shown in FIG. 1, but a hole 310 at the right side 306 of the printer 300 is where the motor gear (not shown) protrudes through in order to engage feed roller gear 311, as well as the gear for the discharge roller (not shown). For normal paper pick-up and feeding, all rollers rotate in forward direction 313. Toward the left side 307 in the example of FIG. 1 is a maintenance station 330. Toward the rear 309 of the printer in this example is located an electronics hoard 390, which contains cable connectors 392 for communicating via cables (not shown) to the printhead carriage 200 and from there to the printhead. Also on the electronics board are typically mounted motor controllers for the carriage motor 380 and for the paper advance motor, a processor and/or other control electronics for controlling the printing process, and an optional connector for a cable to a host computer.
In the prior art printer of FIG. 1, carriage guide rail 382 is part of a metal supporting structure that acts as a type of “backbone” 385 that extends from left side 307 to right side 306 of the printer for support and for attaching printer components. In conventional practice, components of carriage printer 300 are assembled onto this backbone and fastened securely using screws, bolts, clips, and other suitable types of fasteners. A component that is not shown in FIG. 1 (in order to show feed roller 312 more clearly) is a pinch roller assembly that is suspended from backbone 385 and that includes rollers that are pressed against feed roller 312 in order to provide a nip for advancing paper. The backbone itself is fastened in place to the printer base (not shown), again using screws or other suitable fasteners. This conventional assembly method works acceptably, but has a number of drawbacks, including the following:                (i) Fabrication complexity of the conventional backbone. The conventional backbone is typically formed by a series of bends in sheet metal. Sheet metal bending tolerances make fabrication of the backbone to the required tolerances difficult.        (ii) Assembly complexity. Assembly of carriage printer 300 using the conventional backbone arrangement requires a number of fasteners, complicating the assembly sequence. The backbone itself also needs to be attached to the printer base.        
Competitive pressures drive the need to provide high quality printing at lower cost. There is a recognized need to reduce the parts count and complexity of these systems and to simplify printer assembly without compromising image quality and performance.